1. Field of the Invention
This invention relates to a glass composition suitable for use in manufacturing microchannel plates and more particularly applies to a glass composition consisting essentially of silicon dioxide (SiO.sub.2), lead oxide (PbO), bismuth oxide (Bi.sub.2 O.sub.3), boron oxide (B.sub.2 O.sub.3), aluminum oxide (Al.sub.2 O.sub.3), barium oxide (BaO) and cesium oxide (Cs.sub.2 O) which results in an improved microchannel plate having increased electron amplification capability and wherein the surface resistivity of the microchannel is substantially improved over the known prior glass compositions when treated with hydrogen gas.
2. Description of the Prior Art
Glass compositions suitable for use in manufacturing microchannel plates are well know in the art. One example of such a glass composition is disclosed in U.K. Patent Application GB 2 120 232 A filed May 16, 1983.
It is also known in the art to fabricate glass fiber optical devices comprising a clad glass and a core glass. Examples of such glass fiber optical devices are disclosed in U.S. Pat. Nos. 3,589,793, and 3,753,672. U.S. Pat. No. 3,753,672 discloses apparatus and a method for making glass fibers formed of a clad glass and a core glass.
The formation of microchannel plates and the process of making the same is well know in the art. Examples of such art is disclosed in U.S. Pat. Nos. 4,853,020, 4,737,013 and 4,629,486.
The description of the operation of a microchannel plate is known in the art. One example of prior art which describes the operation of a microchannel plate is an article entitled Current Status of the Microchannel Plate by S. Matsuura, S. Umebayashi, C, Okuyama, and K. Oba, which appeared in the IAAA Transactions on Science, Bol. NS-31, No. 1, February 1984 at pages 399 to 403 inclusive.
Another article entitled The Microchannel Image Intensifier by Michael Lampton which appeared in the Scientific American, November, 1981, at pages 62 to 71 inclusive, likewise describes microchannel plate operations.
The use of a microchannel plate as an electron multiplier is also well know in the art. Such devices which utilize microchannel plates are disclosed in U.S. Pat. Nos. 4,714,861; 3,341,730 and 3,128,408. A method for making a channel type electron multiplier is disclosed in U.S. Pat. No. 4,853,020.
In operation, microchannel plate electron multiplier devices are utilized with electromagnetic radiation sources and/or sources of electrons. Electromagnetic radiation received by a device is converted through an appropriate conversion device into electrons and the electrons are utilized as an input to the electron multiplier utilizing a channel type multichannel device. A multichannel device consists of a plurality of continuous path or microchannels through a thin glass plate. The microchannel paths have the walls thereof chemically and thermally treated to form an emissive layer. Secondary emissive properties are imparted to the walls as the result of such treatment. Electrons received at one end of a microchannel are transported through the paths or microchannels. During passage therethrough, each electron subsequently generates a large number of free electrons due to multiple collisions with the electron emissive treated surface.
The known glass compositions and the components present in the glass determine, to some extent the ability for the microchannel to be produced and to be chemically and thermally treated, so as to have appropriate resistivity characteristics such that a large electron multiplication can occur.